Summary

Over the past few years, sewage treatment plants in industrialized nations have begun to reinvent themselves, their operators motivated by tighter regulations and economics to put the byproducts of treatment processes to good use. Aided by new technologies and old technologies put together in new ways, the facilities are becoming more efficient, cutting energy use and—in an increasing number of cases—producing more energy than they need to operate. And with the help of a common, but until recently underappreciated, bacterium, they are getting rid of pollutants for less cost (see sidebar). Treatment plants are becoming the water resource factories of the future, experts say.